The North Central Colorado Urban Area comprises the four contiguous metropolitan statistical areas in the north central region of the State of Colorado: the Denver–Aurora Metropolitan Statistical Area, the Boulder Metropolitan Statistical Area, the Fort Collins-Loveland Metropolitan Statistical Area, and the Greeley Metropolitan Statistical Area. With the exception of southeastern Elbert County, southeastern Park County, and tiny portions of southern Douglas County, the entire North Central Colorado Urban Area is drained by the South Platte River and its tributaries. The North Central Colorado Urban Area is the central, and the most populous, of the three primary subregions of the Front Range Urban Corridor.